EDDA vertex reconstruction

Determining COSY Beam Parameters from Elastic Proton Proton Scattering

From the coplanarity condition for proton proton elastic scattering events measured with EDDA we are able to extract the horizontal position and width of the COSY beam at the EDDA target location. In addition the beam angles x'=dx/ds and y'=dy/ds and the height of the -horizontally mounted- EDDA fiber target are determined.
See the writeup (PostScript) on this topic!

Postscript Pictures of Fit Results for Different Data Samples:

Each PostScript file contains 9 plots: The result of the fit for 25ms, 50ms, and 100ms wide bins in time are displayed for three sets of fit parameters:
  1. Set 1: All parameters are fitted
  2. Set 2: All parameters but y' are fitted
  3. Set 3: All parameters except x' and y' are fitted
Pictures are available for the following runs:
  1. 24.-25. November 1994, data taken during the ramp
    (Run number CH2: 135-179,181-207 C: 211-247)
  2. 29. March 1995, data taken during the ramp
    (Run number CH2: 136-181 C: 119-135)
  3. 30. March 1995, data taken at 2250MeV in the flattop
    (Run number CH2: 20-26,30-46 C: 47-55)
  4. 14.-15. September 1995, data taken during the ramp
    (Run number CH2: 846-875 C: 812-831)
  5. 15. September 1995, data taken at 2250MeV in the flattop
    (Run number CH2: 879-888 C: 890-893)
  6. April/May 1996, data taken during ramp, runs 412-704
    (derived from CH2: 434-446 C: 447-454)
  7. April/May 1996, data taken during ramp, runs 778-1078
    (derived from CH2: 1032-1050 C: 1008-1028)
  8. April/May 1996, data taken during ramp, runs 75-258
    (derived from CH2: 143-163 C: 185-205)
  9. April/May 1996, flat top data 3000MeV/c, runs 705-744
    (derived from CH2: 705-725 C: 729-744)
  10. November/Dezember 1996, data taken during ramp up to 3333MeV/c, runs 310-529
    (derived from CH2: 382-401 C: 362-377)
  11. May/June 1997, data taken during ramp up to 3300MeV/c, runs 35-166
    (derived from CH2: 41-106)
  12. May/June 1997, data taken during ramp up to 3300MeV/c, runs 167-465
    (derived from CH2: 299-355)
  13. November/Dezember 1997, data taken during ramp up to 2700MeV/c, runs 34-65, 222-248, 352-378
    (derived from CH2: 236-243 C: 244-248)
  14. November/Dezember 1997, data taken during ramp up to 2700MeV/c, runs 446-516
    (derived from CH2: 488-516 C: 472-487)
  15. June/July 1998, data taken during flattop @2700MeV/c, runs 1-49, 59-153
    (derived from CH2: 127-153)
  16. June/July 1998, data taken during flattop @2700MeV/c, runs 306-329
    (derived from CH2: 312-321, C: 322-328 )

Data Files of Fit Results for Different Data Samples:

Data items are: 
t     : time since EDDA target startet to move (in ms)
p     : beam momentum (in MeV/c)
x_b   : horizontal beam position (in mm)
y_b   : vertical target position (in mm)
dx_b  : horizontal beam width (in mm FWHM)
x'_b  : horizontal beam angle (in mrad)
y'_b  : vertical beam angle (in mrad)
d_phi : azimuthal angular resolution (in deg FWHM)
  1. 24.-25. November 1994, data taken during the ramp
    (Run number CH2: 135-179,181-207 C: 211-247)
  2. 29. March 1995, data taken during the ramp
    (Run number CH2: 136-181 C: 119-135)
  3. 30. March 1995, data taken at 2250MeV in the flattop
    (Run number CH2: 20-26,30-46 C: 47-55)
  4. 14.-15. September 1995, data taken during the ramp
    (Run number CH2: 846-875 C: 812-831)
  5. 15. September 1995, data taken at 2250MeV in the flattop
    (Run number CH2: 879-888 C: 890-893)
  6. April 1996, data taken during ramp, valid for runs 412-704
    (Run number CH2: 434-446 C: 447-454)
  7. April 1996, data taken during ramp, valid for runs 778-1078
    (Run number CH2: 1032-1050 C: 1008-1028)
  8. April 1996, data taken during ramp, valid for runs 75-258
    (Run number CH2: 143-163 C: 185-205)
  9. April 1996, flat top 3000MeV/c, valid for runs 705-744
    (Run number CH2: 705-725 C: 729-744)
  10. November/Dezember 1996, data taken during ramp up to 3333MeV/c, valid for runs 310-529
    (Run number CH2: 382-401 C: 362-377)
  11. May/June 1997, data taken during ramp up to 3300MeV/c, valid for runs 35-166
    (Run number CH2: 41-106)
  12. May/June 1997, data taken during ramp up to 3300MeV/c, valid for runs 167-465
    (Run number CH2: 299-355)
  13. November/Dezember 1997, data taken during ramp up to 2700MeV/c, runs 34-65, 222-248, 352-378
    (derived from CH2: 236-243 C: 244-248)
  14. November/Dezember 1997, data taken during ramp up to 2700MeV/c, runs 446-516
    (derived from CH2: 488-516 C: 472-487)
  15. June/July 1998, data taken during flattop @2700MeV/c, runs 1-49, 59-153
    (derived from CH2: 127-153)
  16. June/July 1998, data taken during flattop @2700MeV/c, runs 306-329
    (derived from CH2: 312-321, C: 322-328)
comments etc. to H. Rohdjess rohdjess@iskp.uni-bonn.de